Part of vomit will always be stomach acid because it's naturally produced in the stomach as a part of digestion. However, throwing up blood can be a sign of damage to the trachea/esophagus/stomach/liver/duodenum, ruptured stomach ulcers, liver disorders.. the list is long. Basically if you throw up blood and your throat isn't hurting (like it's cut) get to hospital (quickly if any significant amount - ruptured ulcers can kill quickly). In any case - seek medical advice immediately.
Nope. Your stomach will produce more acid in response to food.
If you mean "what is the acid in the stomach", it's primarily HCl (hydrochloric acid).
it could, as sometimes when the acid comes up from the stomach into their mouths, sometimes hurting their throat. It is much like when you throw up, your throat hurts afterwards. So yes it could sometimes cause a cough.
If you mean what is stomach acid in chemical terms? HCL.
That mean it contain old blood as if from oesophagus,stomach and upper small intestine.
It means its bad enough to make you want to throw up or barf
it means see a doctor.
Sounds like acid reflux. Talk to your doctor.
You are having a period
Ranitidine is an anti acid, used for people with gastroparesis or stomach ulcer, also used for acid reflux patience. If by antacid you mean the tablets people chew to neutralize too much stomach acid, like Tums or Rolaids, it is not that kind of antacid. Instead of neutralizing the acid that's already there, it prevents your stomach from making so much acid. Here is a description of how it works, from a medical website: Ranitidine acts in the stomach to decrease the production of stomach acid. It works by blocking histamine H2 receptors that are found on the cells in the stomach lining. A natural body chemical called histamine normally binds to these receptors, causing the cells to produce stomach acid. By blocking the H2 receptors, ranitidine prevents histamine from binding to them. This stops the cells from producing stomach acid.
Having a stomach virus does not mean that the virus is in the stomach. Few germs could live in the acid there. What stomach virus refers to is a virus infection in the entire body that happens to cause nausea and expulsion of the stomach's contents and also diarrhea in the intestines.
If you have blood in your vomit it very well could mean that you have a ulcer. It would be best that you go to a doctor. Better safe then sorry.